Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

New snow and a good dose of wind will create fresh pockets of wind-drifted snow for you to navigate around. Once you lose the wind, you lose the problem. So consider sticking to more sheltered terrain away from the wind-zone. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    West winds will be at work drifting new snow into reactive shallow slabs. These slabs will build in size and distribution across the terrain as new snow piles up. More snow is forecasted for the crest, so expect these slabs to be larger on the western edges of the zone. 

    Use visual clues such as blowing snow or fresh drifts to help you identify slopes of concern. Look for these pillow-like slabs forming on the leeward side of ridges, under cornices, and peppered in the alpine. High wind speeds may push these slabs further down slope than usual, so don't be surprised if you find these forming mid-slope or at lower elevations. 

    The best policy is to simply limit your exposure to steep wind-exposed slopes.  Don’t ignore obvious signs of instability such as shooting cracks under your skis/sled or hard over soft layering. 

    (1/22/2023)

    You may notice shallow instabilties like this on Friday. Look for wind-stiffened snow, cracking,  or snow sliding easily to help you idenitfy areas of concern. 

    Photo: Joe Dellaporta

Avalanche Discussion

Monday is shaping up to be a stormy day for the Cascade Crest. Precipitation amounts should taper the further you move east, with the far eastern mountains only receiving miniscule amounts. However, if you do plan on traveling in western parts of the East-South, keep an eye out for storm instabilities developing during the afternoon hours. New snow will likely bond well to the moist surfaces, but be ready to adjust your travel plans if you notice new snow sliding easily or see shooting cracks within the new snow. 

I traveled into the Ahtanum Meadows area on Wednesday and observed 10-12 inches of new storm snow from the evening of 2/7. We generally found a favorable upper snowpack structure and minimal signs of instability as we traveled. Near ridgetop we did observe signs of recent wind-loading, however, these slabs appeared stubborn on test slopes.

The MLK crust remains a prominent marker in the upper snowpack. Generally we found this layer to be 1-2’ below the snow surface. We still found some weak snow associated with the crust, however, this layer did not show the ability to propagate in snowpack tests in the location we were.  Unsurprisingly, we found the weakest snow associated with this interface (rounding facets) on shaded aspects (NW-N-NE) above 6500 ft. Overall, we found great riding conditions and a fairly strong upper snowpack. You can check out our full observation here. 

Regioni coperte